1. Field of the Invention
The invention particularly concerns a device for transmission of electrical currents to rotating machine parts, especially rotating substrate carriers in process chambers, as well as the application of such devices.
In the conventional contact-making arrangements for rotating shafts, a slip ring arrangement is placed on the rotor shaft. This produces a relatively large diameter of the contact-making tracks with a high circumferential velocity and, thereby, considerable wear and tear on the carbon brushes. Such arrangements employ either drum slip rings, situated alongside each other on the rotor shaft, or plane slip rings, which are arranged on the end of the rotor shaft or alongside each other on an insulating carrier disk. A disadvantage of plane slip rings is the fact that, owing to the different diameters of the slip tracks, the carbon brushes are also subjected to considerable wear. These disadvantages are further intensified if the contact-making devices are required to operate without lubrication, as is the case with arrangements in vacuum process chambers or when operating at high temperatures (see German Publication 29 26 294 and German Publication 30 19 118).